This application relates generally to gas turbine engines and, more particularly, to combustors for gas turbine engine.
Combustors are used to ignite fuel and air mixtures in gas turbine engines. Known combustors include at least one dome attached to a combustor liner that defines a combustion zone. Fuel injectors are attached to the combustor in flow communication with the dome and supply fuel to the combustion zone. Fuel enters the combustor through a dome assembly attached to a spectacle or dome plate.
The dome assembly includes an air swirler secured to the dome plate, and radially inward from a flare cone. The flare cone is divergent and extends radially outward from the air swirler to facilitate mixing the air and fuel, and spreading the mixture radially outwardly into the combustion zone. A divergent deflector extends circumferentially around the flare cone and radially outward from the flare cone. The deflector prevents hot combustion gases produced within the combustion zone from impinging upon the dome plate.
During operation, fuel discharging to the combustion zone combines with air through the air swirler and may form a film along the flare cone and the deflector. This fuel mixture may combust, resulting in high gas temperatures. Prolonged exposure to the increased temperatures increases a rate of oxidation formation on the flare cone, and may result in melting or failure of the flare cone.
To facilitate reducing operating temperatures of the flare cone, at least some known combustor dome assemblies supply cooling air for convection cooling of the dome assembly through a gap extending partially circumferentially between the flare cone and the deflector. Such dome assemblies are complex, multi-piece assemblies that require multiple brazing operations to fabricate and assemble. In addition, during use the cooling air may mix with the combustion gases and adversely effect combustor emissions.
Because the multi-piece combustor dome assemblies are also complex to disassemble for maintenance purposes, at least some other known combustor dome assemblies include one-piece assemblies. Although these dome assemblies facilitate reducing combustor emissions, such assemblies do not supply cooling air to the dome assemblies, and as such, may adversely impact deflector and flare cone durability.
In an exemplary embodiment, a one-piece deflector-flare cone assembly for a gas turbine engine combustor facilitates extending a useful life of the combustor in a cost-effective and reliable manner without sacrificing combustor performance. The one-piece deflector-flare cone assembly is also configured to be secured to an air swirler and to a combustor dome plate within the combustor in a single brazing operation. The cone assembly includes an integral deflector portion and a flare cone portion. The deflector portion includes an integral opening that extends circumferentially through the deflector portion for receiving cooling fluid therein. The deflector opening is also circumferentially in flow communication with the flare cone portion.
During assembly of the combustor, braze rope and braze tape are pre-loaded into respective slots defined within the deflector-flare cone assembly and the air swirler. The cone assembly is then affixed to the air swirler and the combustor dome plate, such that a relative alignment between the cone assembly, the dome plate, and the air swirler, is maintained during a brazing operation. More specifically, the one-piece deflector-flare cone assembly is secured to the air swirler and the combustor dome plate in a single brazing operation. As a result, the deflector-flare cone facilitates assembling the combustor in manner that is more cost-effective and reliable than used to assemble other known combustor assemblies that supply cooling air to the dome assemblies.